How to stop the next Ebola
Hendra is a leafy suburb of Brisbane. Horses walk along the streets, perhaps on their way to the Doomben racecourse. But there are not as many as there should be. You see in 1994 a strange virus began to kill horses and is still striking them down today. What is worse is that this same virus, which is harboured by flying foxes, has killed four humans.
Hendra, as this virus is now called, has no known cure. No drug exists and no commercial pharmaceutical company is going to waste its time devising a vaccine to protect people from a virus that rarely strikes, or a drug that might not be used from one year to the next.
The next Ebola?
Until recently the same was said about the Ebola virus. We first knew that it existed in the 1960s but apart for a few sporadic outbreaks in Africa it hardly seemed much of a threat. But last year West Africa was struck by the Zaire strain of the Ebola virus and people started dropping like ninepins.
The scale of the human tragedy was appalling. More than 10,000 people died and the problem is not over yet. The disease has been contained. People have been more careful. It has been accepted that the ancient burial ritual that removes the foetus from a pregnant woman after her death only serves to spread the disease. Removing the dead woman in a body bag might offend the Gods, but it does protect the living.
Ebola has not been beaten by existing medicines because there were none to hand. ‘The Global Response to Ebola’ was the subject of a fascinating seminar that I attended recently and the message was rather alarming. If the Ebola virus could catch us unaware, might not many others?
Let me just remind you of the science. A virus is a microscopic organism which has its own DNA, surrounded by a protein coat.
Here is a picture of the Ebola virus:
Source: RCSB PDB Molecule of the Month, David Godsell
The thing that distinguishes a virus from a bacteria is that it can only live within the cell of another living thing. In our bodies viruses infect human cells, altering their genetic make-up and changing their function. This is not always a bad thing. We have some friendly viruses that help protect us from dangerous bacteria such as E.coli. They can also lie dormant within a cell, and if they are dangerous they will usually be conquered by the immune system.
But sometimes viruses cause serious problems. Chicken pox, polio, shingles and of course AIDs are amongst them. We deal with them by giving vaccines, which introduce a small amount of the virus into the body, educating the immune system and priming it for a more serious attack. Failing this preventative measure, we can produce anti-viral drugs such as those that fight Aids.
Are we adequately prepared for a new deadly virus?
Vaccines are a multi-billion dollar market dominated by Merck, Sanofi, GlaxoSmithKline and Pfizer. Pumping out protection against influenza, measles, and polio is a good business.
But the question posed at the Oxford seminar was whether the industry could cope with a sudden outbreak of a new deadly virus. There are several that we already know about. Aside from Ebola and Hendra, the list of ‘Outbreak Pathogens’ includes the Marburg virus, Hantavirus (which caused death in Yosemite National Park), Rift Valley Fever and the Nipah virus that broke out in Singapore and Malaysia and led to the culling of a million pigs.
In total there are about fifteen known viruses that have killed humans, but we have no vaccines for them. Frankly they have been too small to worry about, they have come and gone and we simply hope that they won’t suddenly take hold like Ebola.
There is another list of viruses with a more sinister purpose. This is the ‘Category A Priority Pathogens’ list maintained by the US Department of Health. These viruses are ‘easily disseminated’, ‘result in high mortality rates’, ‘might cause public panic and social disruption’ and ‘require special action for public health preparedness.’ In other words they are the viruses that could become the weapons of bio-terrorism, and the list is:
• Small- and other- poxes
• Tularemia and
• Viral haemorrhagic fevers, of which Ebola is one.
So when in November of 2014 Thomas Duncan became the first American to die of Ebola on US soil, the alarm bells were ringing and the degree of political support is one explanation for the speedy response to Ebola.
Immediately teams were sent out into the field. Camps were set up. Volunteers did their best to help the victims. The identity of the virus was established using a high speed gene sequencing machine. Existing drugs were rapidly screened to see if any might work.
Partly thanks to President George Bush’s ‘Project Bioshield’ some work had been done, there were some existing drug candidates and money was made available for further work.
Today the World Health Organisation lists nine vaccines and twelve drugs that have been, or are still, in trials. One vaccine, from Merck, has recently delivered very encouraging results.
This rapid response was the exception to the rule
The response to Ebola was rapid. Usually it takes a decade or more to find new treatments. Research, testing and regulatory approval moves at a glacial pace but, as one member of the Oxford audience put it, ‘this time we are doing in 10-15 weeks what normally takes 10-15 years.’ When faced with a sudden deadly outbreak that might, God forbid, actually threaten American citizens, it seems that drug companies and regulators can turn things around very rapidly, albeit by cutting some corners with possibly dangerous consequences.
So the conclusion of the seminar was rather alarming. The drug industry has traditionally staged large scale trials on diseases that are well established and here to stay. There is plenty of time to study the disease, find solutions and run trials. But killer viruses can spring up at any moment. In the age of global travel these can spread with unprecedented speed and worse still could be used by terrorists. Unless we find a way to prepare for threats that are hard to identify, may never arise, and have no commercial attraction,
Ebola will not be the last major viral killer.